This invention relates to a novel nuclear protein which interacts with the androgen receptor in vivo and in vitro, and which also possesses ATPase activity. The invention concerns also mRNA and DNA sequences encoding said protein.
The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference.
The androgen receptor (AR) belongs to the superfamily of nuclear receptors that are ligand-activated transcription factors capable of regulating transcription of genes containing appropriate response elements, usually within or around the proximal promoter regions (Quigley et al., 1995; Beato et al., 1995; Perlmann and Evans, 1997). After hormone binding, the receptors associate with their cognate DNA motifs and modulate transcription initiation. Nuclear receptors may interact directly with the basal transcription factors associated with RNA polymerase II, such as TFIIB (Blanco et al., 1995; Hadzic et al. 1995; Ing et al., 1992) and TFIIF (McEwan and Gustafsson, 1997), or elicit their actions indirectly via auxiliary regulatory proteins, called coactivators and corepressors (Torchia et al., 1998; Freedman, 1999; McKenna et al., 1999).
In the nucleus, the DNA is folded into a tight chromatin structure that often renders important regulatory sequences inaccessible for sequence-specific transcription factors, including steroid receptors (Kingston et al., 1996). As a consequence, different chromatin remodeling complexes are required to counteract this repressive effect (Bjxc3x6rklund et al., 1999; Lemon and Freedman, 1999; Kingston and Narlikar, 1999). Yeast SWI/SNF was the first complex shown to facilitate the function of gene regulatory proteins in a chromatin environment (Hirschhorn et al., 1992). Mammalian (hSWI/SNF, NURD, RSF), Drosophila (NURF, CHRAC, ACF) and yeast (RSC) homologs of this complex have subsequently been characterized (Kwon et al., 1994; Xue et al., 1998; LeRoy et al., 1998; Mizuguchi et al., 1997; Varga-Weisz et al., 1997; Ito et al., 1999; Tsuchiya et al., 1998). In the yeast, mutation in the components of the SWI/SNF complex results in reduced glucocorticoid (GR) and estrogen receptor (ER) activity, indicating the importance of an intact remodeling complex for steroid receptor activity (Yoshinaga et al., 1992). In addition, co-expression of GR and hbrm (a component of the hSWI/SNF complex) in cells depleted of hbrm restores the GR-dependent transcription (Muchardt and Yaniv, 1993).
The yeast SWI2/SNF2 protein was first described as the subunit responsible for the ATPase activity of the SWI/SNF complex (Khavari et al., 1993; Laurent et al., 1993; Cote et al., 1994). SWI2/SNF2 is the founding member of the family of SNF2-like proteins that share in common a 600-amino-acid-long conserved domain (the Snf2 domain) surrounded by non-conserved regions. The SNF2-like family comprises over 100 members (Eisen et al., 1995), and most of these proteins have no known biological function. However, those members that have been shown to possess well-defined functions all play distinct roles in DNA processing activities, such as replication, repair and/or transcription (Pazin and Kadonaga, 1997; Kingston and Narlikar, 1999). The Snf2 domain contains seven so-called helicase motifs and a consensus region for binding and hydrolysis of ATP. While no helicase activity has experimentally been demonstrated for any of the SNF2-like proteins, the importance of the ATPase activity is well established for many family members (Kingston and Narlikar, 1999). Phylogenetic analysis by Eisen et al. (1995) suggested that the non-conserved regions surrounding the Snf2 domain could be responsible for targeting the ATPase activity to specific compartments of cells.
According to one embodiment, this invention concerns an isolated protein being able to interact with the androgen receptor and having ATPase activity, said protein comprising the sequence of 1466 amino acids as shown in FIG. 1B, or a part thereof having similar biological activity. The protein sequence is also set forth in SEQ ID NO:2 and in GenBank Accession No. AJ132389.
According to another embodiment, the invention concerns a DNA sequence encoding a protein being able to interact with the androgen receptor and having ATPase activity, said protein comprising the sequence of 1466 amino acids as shown in FIG. 1B, or a part thereof having similar biological activity. The nucleotide sequence is set forth in SEQ ID NO:12 and in GenBank Accession No. AJ132389.
According to a third embodiment, the invention concerns an mRNA sequence encoding a protein being able to interact with the androgen receptor and having ATPase activity, said protein comprising the sequence of 1466 amino acids as shown in FIG. 1B, or a part thereof having similar biological activity.